U.S. patent application number 17/372084 was filed with the patent office on 2022-02-03 for thermal runaway suppression element and the related applications.
This patent application is currently assigned to PROLOGIUM TECHNOLOGY CO., LTD.. The applicant listed for this patent is PROLOGIUM HOLDING ING., PROLOGIUM TECHNOLOGY CO., LTD.. Invention is credited to Szu-Nan YANG.
Application Number | 20220037711 17/372084 |
Document ID | / |
Family ID | |
Filed Date | 2022-02-03 |
United States Patent
Application |
20220037711 |
Kind Code |
A1 |
YANG; Szu-Nan |
February 3, 2022 |
THERMAL RUNAWAY SUPPRESSION ELEMENT AND THE RELATED
APPLICATIONS
Abstract
A suppression element includes a passivation composition
supplier and a polar solution supplier. The passivation composition
supplier is capable of releasing a metal ion (A), selected from a
non-lithium alkali metal ion, an alkaline earth metal ion or a
combination thereof, and an aluminum etching ion (B). The polar
solution of the polar solution supplier carries the metal ion (A)
and the aluminum etching ion (B) to an aluminum current collector
to etched through thereof, and the metal ion (A) and the aluminum
ion, generated during the etching, are seeped into the
electrochemical reaction system. Then, the positive active material
is transferred to a crystalline state with lower electric potential
and lower energy, and the negative active material is transferred y
to an inorganic polymer state with higher electric potential and
lower energy to prevent the thermal runaway from occurring.
Inventors: |
YANG; Szu-Nan; (Taoyuan
City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PROLOGIUM TECHNOLOGY CO., LTD.
PROLOGIUM HOLDING ING. |
Taoyuan City
Grand Cayman |
|
TW
KY |
|
|
Assignee: |
PROLOGIUM TECHNOLOGY CO.,
LTD.
Taoyuan City
TW
PROLOGIUM HOLDING ING.
Grand Cayman
KY
|
Appl. No.: |
17/372084 |
Filed: |
July 9, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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63087563 |
Oct 5, 2020 |
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63058205 |
Jul 29, 2020 |
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International
Class: |
H01M 10/653 20060101
H01M010/653; H01M 10/0525 20060101 H01M010/0525; H01M 10/42
20060101 H01M010/42 |
Claims
1. A thermal runaway suppression element, adapted for a lithium
battery, the thermal runaway suppression element comprising: a
passivation composition supplier, for releasing a metal ion (A) and
an aluminum etching ion (B), and wherein the metal ion (A) is
selected from a non-lithium alkali metal ion, an alkaline earth
metal ion or a combination thereof; and a polar solution supplier,
for releasing a polar solution to carry the metal ion (A) and the
aluminum etching ion (B) to an aluminum current collector of the
lithium battery, wherein the aluminum current collector is etched
through by the aluminum etching ion (B) and an aluminum ion is
exchanged, and wherein the metal ion (A) and the aluminum ion are
carried by the polar solution inside the lithium battery and seeped
into the electrochemical reaction system to terminate an
electrochemical reaction.
2. The thermal runaway suppression element of claim 1, wherein the
metal ion (A) and the aluminum etching ion (B) are released when
the passivation composition supplier is dissociated in the polar
solution.
3. The thermal runaway suppression element of claim 1, wherein the
metal ion (A) is selected from a sodium ion, a potassium ion or a
combination thereof.
4. The thermal runaway suppression element of claim 1, wherein the
passivation composition supplier further releases an amphoteric
metal ion (C).
5. The thermal runaway suppression element of claim 1, wherein the
aluminum etching ion (B) is selected from a hydroxide ion or a
nitrate ion.
6. The thermal runaway suppression element of claim 1, wherein the
passivation composition supplier is NaAl(OH).sub.4.
7. The thermal runaway suppression element of claim 1, further
comprising an isolating mechanism to separate the passivation
composition supplier and the polar solution supplier.
8. The thermal runaway suppression element of claim 7, wherein the
isolating mechanism is selected from a protecting layer or a
capsule without holes.
9. The thermal runaway suppression element of claim 8, wherein the
protecting layer or the capsule is made of a thermosensitive
decomposition material or a dissolvable material, which is
dissolved in the polar solution.
10. The thermal runaway suppression element of claim 7, wherein the
polar solution supplier is water-releasing compound decomposed
endothermically to release water, the passivation composition
supplier is anhydrous, and the isolating mechanism is a polymer
layer with holes to cover the passivation composition supplier and
the polar solution supplier.
11. The thermal runaway suppression element of claim 1, wherein the
passivation composition supplier or the polar solution supplier is
attached to a structural supporting material.
12. The thermal runaway suppression element of claim 11, wherein
the structural supporting material is capable of absorbing
solutions.
13. The thermal runaway suppression element of claim 12, wherein
the structural supporting material is selected from a paper, a
polymer fiber, a gel polymer or a glass fiber.
14. The thermal runaway suppression element of claim 1, further
comprising a metal mesh frame with through holes, wherein the
passivation composition supplier and the polar solution supplier
are filed in the through holes.
15. The thermal runaway suppression element of claim 1, wherein the
polar solution supplier is water-releasing compound decomposed
endothermically to release water.
16. The thermal runaway suppression element of claim 1, further
comprising a film-forming agent to mix with the passivation
composition supplier and/or the polar solution supplier to form a
film.
17. The thermal runaway suppression element of claim 1, wherein the
polar solution supplier is added with a hydrophilic material with a
boiling point higher than the pure water.
18. The thermal runaway suppression element of claim 1, wherein the
passivation composition supplier is composed of more than two
compounds.
19. A battery structure capable of suppressing thermal runaway,
including a lithium battery with an aluminum current collector,
wherein a thermal runaway suppression element of claim 1 is
disposed on an open-side surface of the aluminum current
collector.
20. The battery structure of claim 19, further comprising another
lithium battery, and the thermal runaway suppression element is
located between the two lithium batteries.
21. The battery structure of claim 19, further comprising a
U-shaped metal sheet disposed between the two main bodies, wherein
the U-shaped metal sheet includes two parallel arms and a cross
member connected thereof, and the two parallel arms and the cross
member form a space to contain the thermal runaway suppression
element.
22. The battery structure of claim 19, further comprising a
restricting layer for an etching direction, disposed surrounded a
side wall of the thermal runaway suppression element.
23. The battery structure of claim 19, wherein the aluminum current
collector includes a groove at the open-side surface, wherein the
passivation composition supplier and the polar solution supplier
are filed in the groove.
24. The battery structure of claim 23, wherein the groove is formed
by a plurality of bumps located on the aluminum current
collector.
25. The battery structure of claim 24, wherein the bumps are made
of a metal, a glass or a polymer, which is inert to thermal runaway
suppression element.
26. The battery structure of claim 19, wherein the aluminum current
collector includes a plurality of auxiliary slots at the open-side
surface, which do not penetrate through the aluminum current
collector, wherein the auxiliary slots is used to facilitate
etching.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application claims benefit under 35 U.S.C..sctn. 119(a)
of U.S. Provisional Patent Application No. 63/058,205 filed Jul.
29, 2020 and U.S. Provisional Patent Application No. 63/087,563
filed Oct. 5, 2020, and the entire contents of which are hereby
incorporated by reference for all purposes.
BACKGROUND OF THE INVENTION
Field of Invention
[0002] The present invention relates to a safety mechanism of the
lithium batteries, in particular to a thermal runaway suppression
element disposed in the lithium batteries and the related
applications.
Related Art
[0003] Because lithium-ion batteries are widely used in various
products, such as vehicles, wearable products for consumers and
industrial applications, portable devices and energy storage
devices and so on, they are almost applied in all areas of human
daily life. However, the event of accidents for the lithium-ion
batteries are heard from time to time, such as the fire or
explosion of mobile phone batteries and electric vehicles. These
are all because the lithium batteries still lack comprehensive and
effective solutions for safety issues.
[0004] The main cause of unsafe event for fire or explosion in the
lithium batteries is the thermal runaway. And the main cause of the
thermal runaway of the lithium batteries is heat, which is the
exothermic reactions result from the thermal cracking, induced by
the elevated temperature, of the SEI (solid electrolyte interface)
film, the electrolyte, the binder, and the positive and negative
active materials in the battery. The current methods for
suppression thermal runaway can be classified into two types:
outside the battery cell and inside the battery cell, depending on
the activated location for safety mechanism. For the type of
outside the battery cell, a monitoring system is utilized, which
uses digital arithmetic simulation. For the type of inside the
battery cell, it can be further divided into physical or chemical
methods. In the digital monitoring system outside the battery cell,
the dedicated protection circuit and the dedicated management
system on the outside of the battery cell are utilized to enhance
the safety monitoring of the battery during the usage process. For
the physical type of inside the battery cell, such as thermal
shutdown separator, at elevated temperature for the battery cell,
the holes of the separator are closed to block the passage of the
ions.
[0005] For the chemical type of inside the battery cell, it can be
defined as a scale controlled type or an electrochemical reaction
type. In the scale controlled type, the flame retardant is added
into the electrolyte to control the scale of the thermal runaway.
The examples of the electrochemical reaction types are as follows:
[0006] a. The monomer or oligmar is added into the electrolyte. The
polymerization will be occurred when the temperature rises to
reduce the rate of the ion migration. Therefore, the ionic
conductivity decreases as the temperature rises, and the
electrochemical reaction rate in the cell slows down; [0007] b. A
positive temperature coefficient (PTC) resistance material is
sandwiched between the positive electrode layer or the negative
electrode layer and the adjacent current collecting layer. When the
temperature of the battery cell is elevated, the electrical
insulation ability is enhanced. The electric power transmission
efficiency between the positive electrode layer or the negative
electrode layer between the adjacent current collecting layer is
reduced and the electrochemical reaction rate is also decreased;
and [0008] c. A modified layer is formed on the surface of the
positive active material. When the temperature of the battery cell
is elevated, the modified layer is transformed into a dense film,
which increases the resistance of the charge transfer to reduce the
electrochemical reaction rate.
[0009] However, the above methods are aimed only for passive
blocking the ion/electron migration pathway to reduce the heat
generation, not for the main source to generate the maximum energy
to cause the thermal runaway and the main reaction body of the
entire electrochemical reaction, i.e. the active materials.
[0010] Therefore, this invention provides a thermal runaway
suppression element of lithium batteries and the related
applications by decreasing the thermal energy leading to thermal
runaway of the active materials to mitigate or obviate the
aforementioned problems.
SUMMARY OF THE INVENTION
[0011] It is an objective of this invention to provide a brand new
thermal runaway suppression element and the related applications,
which is capable of transferring the positive active material with
lithium-ion extraction from an original state with higher electric
potential and higher energy to a crystalline state of the metal
oxide with lower electric potential and lower energy, and
transferring the negative active material with lithium-ion
insertion from an original state with lower electric potential and
higher energy to an inorganic polymer state with higher electric
potential and lower energy. Therefore, the electrochemical reaction
pathway is blocked to prevent the thermal runaway from
occurring.
[0012] Also, it is another objective of this invention to a brand
new thermal runaway suppression element and the related
applications, which is disposed outside of the lithium battery.
Therefore, it will not affect the performance of the
electrochemical reaction system of the lithium battery.
[0013] It is further objective of this invention to a brand new
thermal runaway suppression element and the related applications.
The aluminum current collector is etched through, and the metal ion
(A) and the aluminum ion, generated during the etching, are seeped
into the electrochemical reaction system of the lithium battery.
The positive active material with lithium-ion extraction and the
negative active material with lithium-ion insertion are transferred
to a lower energy state. Therefore, the voltage of the whole
battery is decreased and the electrochemical reaction pathway is
blocked to prevent the thermal runaway from occurring.
[0014] In order to implement the abovementioned, this invention
discloses a thermal runaway suppression element, which includes a
passivation composition supplier and a polar solution supplier. The
passivation composition supplier is capable of releasing a metal
ion (A), selected from a non-lithium alkali metal ion, an alkaline
earth metal ion or a combination thereof, and an aluminum etching
ion (B). The polar solution supplier releases a polar solution to
carry the metal ion (A) and the aluminum etching ion (B) to an
aluminum current collector of the lithium battery. The aluminum
current collector is etched through by the aluminum etching ion
(B), and the metal ion (A) and the aluminum ion, generated during
the etching, are seeped into the electrochemical reaction system of
the lithium battery. The positive active material with lithium-ion
extraction and the negative active material with lithium-ion
insertion are reacted with the metal ion (A) and are transferred to
a lower energy state. Therefore, the voltage of the whole battery
is decreased and the electrochemical reaction pathway is blocked to
prevent the thermal runaway from occurring.
[0015] This invention further discloses a battery structure capable
of suppressing thermal runaway, which includes a lithium battery
with an aluminum current collector. The above-mentioned thermal
runaway suppression element is disposed on an open-side surface of
the aluminum current collector.
[0016] Further scope of applicability of the present invention will
become apparent from the detailed description given hereinafter.
However, it should be understood that the detailed description and
specific examples, while indicating preferred embodiments of the
invention, are given by way of illustration only, since various
changes and modifications within the spirit and scope of the
invention will become apparent to those skilled in the art from
this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The present invention will become more fully understood from
the detailed description given hereinbelow illustration only, and
thus are not limitative of the present invention, and wherein:
[0018] FIGS. 1A-1C are schematic diagrams of the embodiments of the
thermal runaway suppression element of this invention.
[0019] FIG. 2 is schematic diagram of another embodiment of the
thermal runaway suppression element of this invention.
[0020] FIGS. 3A-3C are schematic diagrams of the embodiments of the
layered thermal runaway suppression element of this invention.
[0021] FIGS. 4A-4H are schematic diagrams of the embodiments of the
thermal runaway suppression element applied for the lithium
batteries of this invention.
[0022] FIG. 5A is an XRD diffraction pattern in which the
concentrations of 30% NaOH.sub.(aq), 30% NaAl(OH).sub.4(aq), 30%
NaCl.sub.(aq), 10% LiOH.sub.(aq), and 30% KOH.sub.(aq) react with
the positive active material with lithium-ion extraction.
[0023] FIG. 5B is the XRD diffraction pattern before and after the
negative active material with lithium-ion insertion is exposed to
sodium/potassium ions and aluminum ions.
[0024] FIG. 6A shows the voltage and temperature curve for the
thermal runaway testing of a conventional lithium battery cell.
[0025] FIG. 6B shows the voltage and temperature curve for the
lithium battery cell with thermal runaway suppression of the
present invention.
[0026] FIGS. 7A to 7C are images of the results of dropping
different solutions selected from pure water, NaOH.sub.(aq) and
NaAl(OH.sub.4).sub.(aq) respectively on a cathode with a 100% SOC
(state of charge).
[0027] FIGS. 8A to 8C are the images for the results of dropping
different solutions selected from pure water, NaOH.sub.(aq) and
NaAl(OH.sub.4).sub.(aq) respectively on a anode with a 100%
SOC(state of charge).
[0028] FIG. 8D is the image of FIG. 13C, which the foam is clamped
by a jig.
[0029] FIGS. 9A and 9B are SEM diagrams of the cathode with a 40%
SOC and with a 100% SOC respectively, which 30% sodium hydroxide
was dropped over about 1 hour.
[0030] FIGS. 10A and 10B are SEM diagrams of the anode with a 40%
SOC and with a 100% SOC respectively, which 30% sodium hydroxide
was dropped over about 1 hour.
[0031] FIGS. 11A and 11B are thermograms of the differential
scanning calorimeter for the cathode and the anode using 20%
NaAl(OH.sub.4).sub.(aq).
DETAILED DESCRIPTION OF THE INVENTION
[0032] The present invention will be described with respect to
particular embodiments and with reference to certain drawings but
the invention is not limited thereto but only by the claims Any
reference signs in the claims shall not be construed as limiting
the scope. The drawings described are only schematic and are
non-limiting. In the drawings, the size of some of the elements may
be exaggerated and not drawn on scale for illustrative
purposes.
[0033] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the general inventive concept. As used herein, the singular forms
"a", "an" and "the" are intended to include the plural forms as
well, unless the context clearly indicates otherwise. Unless
otherwise defined, all terms (including technical and scientific
terms) used herein have the same meaning as commonly understood by
one of ordinary skill in the art to which example embodiments
belong. It will be further understood that terms, such as those
defined in commonly used dictionaries, should be interpreted as
having a meaning that is consistent with their meaning in the
context of the relevant art and should not be interpreted in an
idealized or overly formal sense unless expressly so defined
herein.
[0034] Reference throughout this specification to "one embodiment"
or "an embodiment" means that a particular feature, structure or
characteristic described in connection with the embodiment is
included in at least one embodiment of the present invention. Thus,
appearances of the phrases "in one embodiment" or "in an
embodiment" in various places throughout this specification are not
necessarily all referring to the same embodiment, but may.
Furthermore, the particular features, structures or characteristics
may be combined in any suitable manner, as would be apparent to one
of ordinary skill in the art from this disclosure, in one or more
embodiments.
[0035] First, the invention is related to a thermal runaway
suppression element, which includes a passivation composition
supplier and a polar solution supplier. The passivation composition
supplier is capable of releasing a metal ion (A) and an aluminum
etching ion (B). The polar solution supplier releases a polar
solution to carry the metal ion (A) and the aluminum etching ion
(B) to etch an aluminum current collector of the lithium battery.
After the aluminum current collector, i.e. the positive current
collector, is etched through by the aluminum etching ion (B), and
the metal ion (A), the residual aluminum etching ion (B) and the
aluminum ion, generated during the etching, are seeped into the
electrochemical reaction system of the lithium battery. The
positive active material with lithium-ion extraction and the
negative active material with lithium-ion insertion are reacted to
transfer to a lower energy state. Therefore, the electrochemical
reaction pathway is blocked to prevent the thermal runaway from
occurring.
[0036] The metal ion (A), selected from a non-lithium alkali metal
ion, an alkaline earth metal ion or a combination thereof. When the
metal ion (A) is selected from the non-lithium alkali metal ion,
which is preferably selected from a sodium ion, a potassium ion or
a combination thereof. When the metal ion (A) is selected from the
alkali earth metal ion, which is preferably selected from a
beryllium ion, a magnesium ion or a calcium ion. The aluminum
etching ion (B) is selected from an alkaline material, such as a
hydroxide ion, or an acidic material, such as a nitrate ion. Also,
the passivation composition supplier may further include an
amphoteric metal ion (C), which is preferably selected from an
aluminum ion or a zinc ion. The passivation composition supplier is
a solution or an anhydrous powder. The above-mentioned "carry"
means that the polar solution is served as a transmission medium
for the metal ion (A) and the aluminum etching ion (B).
[0037] For the positive active material, the metal ion (A) will
obtain electrons from the positive active material with lithium-ion
extraction and deposit thereof, and then further migrate to occupy
the positive of the lithium-ion extraction, or the intercalation.
The positive active material with lithium-ion extraction is
transferred from an original state with higher electric potential
and higher energy to a reactant state, i.e. a crystalline state of
the metal oxide, with lower electric potential and lower energy.
Moreover, it is unstable in structure and easy to release oxygen
substance (O.sub.2, O.sub.2.sup.-, O.sup.-) due to the loss of
lithium atoms in the original state of the positive active
material. The metal atoms formed by the metal ion (A) with
electrons, such as the sodium atoms will be driven by thermal
energy to fill the positive of the lithium-ion extraction, or
intercalation, and relocate the lattice to form a new stable state,
and at the same time, thermal energy is consumed. Further, when the
metal ion (A) with electrons is filled into the positive material,
the characteristics of the metal ion (A) will be induced. For
example, if the sodium are filled into the positive material, this
new stable state structure will represent some of the
characteristics of the sodium, due to contain the sodium, such as
increased adsorption of moisture. That will increase the insulating
properties of the electrodes and result in a decrease in
performance. For the negative active material, the metal ion (A),
the aluminum ion, generated during the etching, and a further added
amphoteric metal ion (C) will react with the negative active
materials with lithium-ion insertion. The negative active material
with lithium-ion insertion is transferred from an original state
with lower electric potential and higher energy to an inorganic
polymer state with higher electric potential and lower energy.
Therefore, this invention can achieve to decrease the electric
potential difference of the positive and the negative active
materials and the voltage of the whole battery, by applying the
additional metal ion (A), the aluminum ion and or further added
amphoteric metal ion (C), to block the electrochemical reaction
pathway to effectively avoid the thermal runaway of the
battery.
[0038] Furthermore, for above-defined where the positive active
material is transferred from the state with higher electric
potential and higher energy to the crystalline state with lower
electric potential and lower energy, the detailed description is
provided below. The positive active material is in the state with
lithium-ion extraction and the electric potential is higher. Also,
because of the unstable crystal lattice, the crystal lattice is
easy to collapse and has a higher ability to release oxygen, and to
release thermal energy violently. Therefore, in the
above-mentioned, it is defined that the positive active material is
in the state with higher electric potential and higher energy. When
the metal ion (A) with electrons fills the positions where
lithium-ion is extracted or the intercalations, the electric
potential of the positive active material is reduced, and the
crystal lattice of the positive active material is relatively
stable. Also, the stability of the crystal lattice of the positive
active material is higher, and the ability of the oxygen-releasing
is reduced, and the ability to release thermal energy violently is
lowered. Therefore, in the above-mentioned, it is defined that the
positive active material is in the passivation state after reacting
with the metal ion (A) is defined as the crystalline state with
lower electric potential and lower energy.
[0039] For above-defined where the negative active material is
transferred from the state with lower electric potential and higher
energy to the state with higher electric potential and lower
energy, the detailed description is provided below. The negative
active material is in the state with lithium-ion insertion and the
electric potential is lower. In addition, because the negative
active material receives the oxygen released from the positive
active material, the negative active material is prone to violently
combust and release thermal energy. Therefore, the negative active
material is unstable and has a higher ability to release thermal
energy. Therefore, in the above-mentioned, it is defined that the
negative active material is in the state with lower electric
potential and higher energy. When the metal ion (A), the aluminum
ion or the further added amphoteric metal ion (C), act with the
negative active material with lithium-ion insertion, the
lithium-ion is captured and form the polymer compound with the base
material of the negative active material, such as silicon-carbon.
As well as the reduction of the ability to release oxygen of the
positive active material, the ability of the negative active
material to release thermal energy violently is lowered. Therefore,
in the above-mentioned, it is defined that the negative active
material is in the passivation state after reacting with the metal
ion (A), the aluminum ion or the further added amphoteric metal ion
(C), is defined as the polymer compound state with higher electric
potential and lower energy. In this state, the negative active
material is transformed to the geopolymer, which is a green
cement.
[0040] In this embodiment, the passivation composition supplier
includes at least one compound, which is capable of dissociation
and releasing the metal ion (A) and the aluminum etching ion (B),
such as NaOH, KOH, NaNO.sub.3, KNO.sub.3, or the like. The compound
capable of providing the amphoteric metal ion (C) may be
AlCl.sub.3, AlBr.sub.3, AlI.sub.3, Al(NO.sub.3).sub.3, AlClO.sub.4,
AlF.sub.3, AlH.sub.3, Zn(OH).sub.2, or the like. Also, the
passivation composition supplier may be a compound capable of
providing the metal ion (A), the aluminum etching ion (B) and the
amphoteric metal ion (C), such as NaAl(OH).sub.4 or the like. But
these are just examples, not intended to limit the type and
quantity of compounds used in the present invention. Furthermore,
the passivation composition supplier may be in an anhydrous state
or a solution state. In the solution state, for example, it has a
higher concentration, 80%-50%, with lower etching ability and
higher stability. Therefore, it is necessary to adjust the
concentration by the polar solution to demonstrate the etching
ability for the aluminum current collector to form the through
holes. In case of the passivation composition supplier is in the
anhydrous state, the polar solution can dissociate the passivation
composition supplier to release the metal ion (A) and the aluminum
etching ion (B) or even the amphoteric metal ion (C). Moreover, the
concentration of the aluminum etching ion (B), such as the
hydroxide ion, is adjusted by the polar solution to demonstrate the
etching ability for aluminum, such as 30%-20%.
[0041] The polar solution supplier is water-releasing compound
decomposed endothermically to release water or a pure water. The
polar solution is used to dissociate the passivation composition
supplier to release the metal ion (A) and the aluminum etching ion
(B) or even the amphoteric metal ion (C), and adjust the
concentration of the aluminum etching ion (B) to demonstrate the
etching ability for aluminum. Also, due to the fluidity of the
polar solution, the metal ion (A), the aluminum etching ion (B) and
the aluminum ion, generated during the etching, are carried by the
polar solution to seep into the electrochemical reaction system of
the lithium battery.
[0042] The thermal runaway suppression element of this invention
may further include an isolating mechanism, which can avoid the
instability caused by direct contact of different materials between
the passivation composition supplier and the polar solution
supplier. The isolating mechanism may be a protecting layer or a
capsule without holes, or a polymer film with holes, which may
further include the film-forming agent below.
[0043] In case of the protecting layer or the capsule without
holes, take the protecting layer for example, the protecting layer
is composed of a thermosensitive decomposition material or a
dissolvable material, which is dissolved in the polar solution. The
temperature of the thermosensitive decomposition material to be
decomposed is 70-130.degree. C. The protecting layer and the
capsule are both used to separate the passivation composition
supplier and the polar solution supplier, but have different
applications. The protecting layer is used to isolate the film-type
material by coating the protecting layer on the outer surface of
the single-layer or multiple layers film-type material. The capsule
is used to isolate the powder or liquid material to divide into
portions in the capsule to avoid direct contact between the two
different materials. The polymer film with through holes is used to
cover the materials in a non-fluid state. When the polar solution
supplier releases the polar solution, the polar solution will
contact to the passivation composition supplier via the through
holes as a transmission path. The material of the polymer film may
be the film-forming agent, as described below.
[0044] The above-mentioned water-releasing compound decomposed
endothermically to release water may be selected from Al(OH).sub.3,
Al(OH).sub.3.H.sub.2O, Mg(OH).sub.2, NH.sub.4H.sub.2PO.sub.4,
NaHCO.sub.3, CH.sub.3COONa.3H.sub.2O, ZnOB.sub.2O.sub.3H.sub.2O,
Na.sub.2B.sub.4O.sub.7.10H.sub.2O, anhydrous CaCl, CaCl.H.sub.2O,
CaCl.2H.sub.2O, CaCl.4H.sub.2O, MgCl.6H.sub.2O,
KAl(SO.sub.4).sub.2.12H.sub.2O, Zn(OH).sub.2,
Ba(OH).sub.2.8H.sub.2O, LiOH, or a combination thereof.
[0045] The thermosensitive decomposition material, which is
selected from paraffin oil, microcrystalline wax, polyethylene wax,
low density PE(polyethylene), poly(trans-1,4-butadiene),
poly(tetramethylene oxide), isotactic poly(methyl methacrylate),
poly(ethylene oxide), poly(ethylene adipate), isotactic
poly(l-butene), poly(ethylene). Also, the thermosensitive
decomposition material is mixed with a mineral oil to lower
softening points.
[0046] In the invention, the protecting layer of the thermal
runaway suppression element is made of the thermosensitive
decomposition material or the water-releasing material decomposed
endothermically. Therefore, the own thermal energy of the battery
is utilized to trigger the thermal runaway suppression element to
release the metal ion (A) and the aluminum etching ion (B), and the
ability to etch aluminum current collector. For example, when the
polar solution supplier is selected from the water-releasing
materials, the material of the protecting layer, used to
encapsulate the passivation composition supplier, is selected from
a material, which is easy to dissolve in water. Therefore, the
water-releasing material decomposed endothermically is served as
the thermal trigger. When the material of the polar solution
supplier is the pure water, the thermosensitive decomposition
material, which cannot dissolve in water, is used to encapsulate
the water. Therefore, the thermosensitive decomposition material is
served as the thermal trigger. In order to increase the
volatilization temperature of the polar solution, a high-boiling
hydrophilic material may be added in the polar solution supplier,
such as glycerin or DMSO (dimethyl sulfoxide).
[0047] Moreover, the passivation composition supplier and/or the
polar solution supplier may further mix with a film-forming agent
to form a film-type thermal runaway suppression element. For
example, Please see FIG. 1A, the passivation composition supplier
12 and the polar solution supplier 14 is mixed with a film-forming
agent 16 required a solvent to form a film 10 by mixing, coating,
drying and pressing processes. In other example, a film-forming
agent 16 without solvent required, is used to mix with the
passivation composition supplier 12 and the polar solution supplier
14 to form a film 10 by a thermal pressing process. Therefore, the
drying process to remove the solvent is not necessary. The
film-forming agent 16 without solvent required may be the
polytetrafluoroethylene (PTFE). On the other hand, the film-forming
agent 16 required a solvent is selected preferably from a material
to remove the solvent at around 80.degree. C., such as
poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) using the
acetone as the solvent, polyurethane (PU) using the butanone as the
solvent, or styrene-butadiene rubber (SBR), carboxyl methyl
cellulose (CMC) or polyacrylic acid (PAA) using the water as the
solvent. In case of different materials of the passivation
composition supplier 12 and the polar solution supplier 14 are
mixed together, above-mentioned isolating mechanism has to be
formed on one of the surface of the passivation composition
supplier 12 and the polar solution supplier 14 to contact thereof.
For example, the passivation composition supplier 12 and the polar
solution supplier 14 is encapsulated by the capsule 26 to separate
the passivation composition supplier 12 and the polar solution
supplier 14, as refer to FIG. 1B. The particle size of the capsule
26 is 1-100 microns preferably. And the process of using the
material of the capsule 26 to encapsulate the supplier 12, 14 may
be a physical or chemical process. The physical process may be, for
example, a solid-liquid phase change based on temperature change or
solvent volatilization. The chemical process may be the
polymerization of small monomers. When the polar solution supplier
14 is selected form the water-releasing compound, and the
passivation composition supplier 12 is in an anhydrous state, the
water-insoluble polymer film 23 with through holes 25 is used to
cover the passivation composition supplier 12, as shown in FIG. 1C,
to reduce the chance of contact between the passivation composition
supplier 12 and the polar solution supplier 14. When the polar
solution supplier 14 releases water, induced by the elevated
temperature, the water will react with the passivation composition
supplier 12 via the through holes 25 to form a liquid. Then the
liquid will flow out from the through holes 25 to perform the
follow-up reactions, such as etching the aluminum current
collector.
[0048] Moreover, a substrate may be utilized to comply with the
requirement of forming the film. The film-forming agent is not
necessary. For example, please to FIG. 2, the polar solution
supplier 14 of the thermal runaway suppression element 10 is
attached to a structural supporting material 22 to form a film. The
passivation composition supplier 12 is mixed with the film-forming
agent 16 to form a film 17. To avoid the instability caused by
direct contact of the passivation composition supplier 12 and the
polar solution supplier 14, a protecting layer 18 is coated on the
outer surface of the structural supporting material 22. The
structural supporting material 22 may be made of a polymer, for
example, polyacrylic acid (PAA), sodium polyacrylate (sodium
polyacrylate), carboxymethyl cellulose (CMC), polyurethane polymer,
guar-gum, alginic acid sodium salt, polyethyleneimine (PEI),
polyethylene oxide (PEO), and polyvinypirrolidone (PVP). When the
structural supporting material 22 is fibers, such as a non-woven
fabric, and the material may be polypropylene (PP), polyethylene
terephthalate (PET) etc. or glass fibers. The structural supporting
material 22 may also be composed of polymethyl methacrylate (PMMA)
and polycarbonates (PC). In addition, when the structural
supporting material 22 is selected from materials that is in a gel
state capable of absorbing solutions, such as sodium alginate and
sodium polyacrylate, which can directly absorb the compounds in the
solution state. When the structural supporting material 22 is
selected from materials that is in a gel state, other structural
supporting materials with holes, such as non-woven fibers, may also
be mixed. The material of the capsule 26 is determined by the
compound to be contained. For example, when the material of the
capsule 26 is easy to dissolve in water, which cannot use to
contain the pure water, the material is selected from gelatin, gum
arabic, chitosan, sodium caseinate, starch, lactose, maltodextrin,
poly-l-lysine/alginate, polyethyleneimine/alginate, calcium
alginate, polyvinyl alcohol. When the material of the capsule 26 is
not easy to dissolve in water, the material is selected from ethyl
cellulose, polyethylene, polymethacrylate, cellulose nitrate,
silicones, paraffin, carnauba wax, stearic acid, fatty alcohols,
stearyl alcohol, fatty acids, hydrocarbon resin, monoacyl glycerol,
diacyl glycerol and triacyl glycerol.
[0049] For example, when the polar solution supplier 14 releases
the pure water, the material of the capsule 26, used to contain the
pure water, is selected from the thermosensitive decomposition
material, which is not easy to dissolve in water. The passivation
composition supplier 12 may be not encapsulated by the capsule, or
encapsulated by the capsule 26 made of a material which is easy to
dissolve in water.
[0050] The above-mentioned protecting or film forming methods for
the passivation composition supplier 12 and the polar solution
supplier 14 can be combined with each other, and are not limited
only by those the drawings or the descriptions. For example, when
the passivation composition supplier 12 is composed of two
compounds 121, 122, the compound 121 is encapsulated with the
capsule 26, and mixed with the polar solution supplier 14 and the
film-forming agent 16 by mixing, coating, drying and pressing
processes to form a first film 28. The compound 122 is encapsulated
with a capsule 26 and mixed with the film-forming agent 16 by
mixing, coating, drying and pressing processes to form a second
film 29. The second film 29 is attached to a surface of the first
film 28 to form a layered structure, as shown in FIG. 3A.
[0051] Further, FIGS. 3B, 3C are the other embodiments of the
thermal runaway suppression element 10. Please refer to FIG. 3B,
the compound 122 is solution-type and attached to the structural
supporting material 22 with a protecting layer 18 encapsulation.
One of the compound 121 is mixed with the polar solution supplier
14 and the film-forming agent 16 and encapsulated with the capsule
26 to form the film. Please refer to FIG. 3C, both the compounds
121, 122 are mixed with the polar solution supplier 14 and the
film-forming agent 16 and encapsulated with the capsule 26 to form
the film, respectively. The protecting or film forming methods may
be varied or combined by the person skilled art. Such variations
are not to be regarded as a departure from the spirit and scope of
the invention.
[0052] Please see FIGS. 4A-4B, which are the battery structure with
the thermal runaway suppression element according to this
invention. Under such structure, due to the thermal runaway
suppression element is disposed outside the lithium battery, it
will not affect the operation of the electrochemical reaction
system. Please refer to FIG. 4A, the thermal runaway suppression
element 10 is disposed on the outer surface of the positive current
collector 301 of the lithium battery 30. The positive current
collector 301 is an aluminum current collector. The lithium battery
30 includes a positive current collecting layer 301, a negative
current collecting layer 302, a glue frame 303, an electrochemical
reaction system. The glue frame 303 is sandwiched between the
positive current collecting layer 301 and the negative current
collecting layer 302. One end of the glue frame 303 is adhered to
the positive current collecting layer 301 and the other end of the
glue frame 303 is adhered to the negative current collecting layer
302. The positive current collecting layer 301, the negative
current collecting layer 302 and the glue frame 303 form an
enclosed space. The electrochemical reaction system arranged in the
enclosed space, which includes a positive active material layer 304
adjacent to the positive current collecting layer 301 and a
negative active material layer 305 adjacent to the negative current
collecting layer 302. The separator 306 is located between the
positive active material layer 304 and the negative active material
layer 305 and has ion conduction characteristics and electrical
insulation properties. The electrolyte system is located in the
enclosed space and impregnated or mixed in the positive active
material layer 304, the negative active material layer 305 and the
separator 306 for use in ion transfer. Moreover, the positive
active material layer 304 and the negative material layer 305 may
further include the electrically conductive materials and the
adhesive materials. Since these parts are not technical features of
this invention, the detailed description is omitted herein.
[0053] In addition, the material of the separator 306 is composed
of a solid electrolyte, or an electrical insulation layer with
holes formed of a polymer material with coating on its surface by
the ceramic powders. Also, the separator 306 may also be formed by
stacking only ceramic powders by using an adhesive. The ceramic
powders may not have ion conductivity, or may also have ion
conductivity.
[0054] The positive current collecting layer 301, the negative
current collecting layer 302, and the glue frame 303 are used as
packaging component of the battery 30. The electrochemical reaction
system of the battery 30 is protected by this packaging component
and isolated from the outer environment. The glue frame 303 is made
of a polymer material. As long as it can be adhered to the surfaces
of the positive and negative current collecting layers 301, 302 and
is durable to the electrolyte system. However, the thermosetting
resin is preferable, for example, silicone. The negative active
material may be a carbon material, a silicon-based material, or a
mixture thereof. Examples of carbon materials include graphitized
carbon materials and amorphous carbon materials, such as natural
graphite, modified graphite, graphitized mesophase carbon
particles, soft carbons, such as cokes, and some hard carbons.
Silicon-based materials include silicon, silicon oxides,
silicon-carbon composite materials, and silicon alloys.
[0055] The thermal runaway suppression element 10 of the invention
is disposed on the outer surface of the positive current collector
301 of a lithium battery 30. The thermal runaway suppression
element 10 releases the metal ion (A), the aluminum etching ion (B)
and the polar solution when the temperature reaches the
predetermined temperature, such as 70-130.degree. C. The positive
current collector 301 is etched through and the aluminum ions are
exchanged during the etching to seep into the lithium battery 30 to
react with the positive active material with lithium-ion extraction
and the negative active material with lithium-ion insertion.
[0056] Please see FIG. 4B, which is another embodiment of the
thermal runaway suppression element according to this invention
applied to the battery. In this embodiment, the thermal runaway
suppression element 10 can be disposed between two stacked lithium
batteries 30. When the two stacked lithium batteries 30 are
connected in parallel, a tab is utilized to connect thereof. Also,
please refer to FIG. 4C, the thermal runaway suppression element 10
according to this invention further includes a U-shaped metal sheet
32, which is made of a material can be etched by the thermal
runaway suppression element 10 or a metal mesh. The U-shaped metal
sheet 32 includes two parallel arms 321 and a cross member 322
connected thereof, and the two parallel arms 321 and the cross
member 322 form a space 323 to contain the thermal runaway
suppression element 10. One of the parallel arm 321 is disposed on
the positive current collector 301 of the lithium battery 30, and
another parallel arm 321 is disposed on the negative current
collector 302 of the another lithium battery 30. Therefore, the two
lithium batteries 30 are electrically connected. Or as shown in
FIG. 4D, the thermal runaway suppression element 10 according to
this invention further includes a metal mesh frame 33 with through
holes 331. The passivation composition supplier and the polar
solution supplier are filed in the through holes 331. The metal
mesh frame 33 is used as a container for structural supporting and
used for electrical connection. In the above-mentioned embodiments,
the thermal runaway suppression element 10 are located between the
two stacked lithium batteries 30, which are connected in parallel
or in serial.
[0057] Please refer to FIG. 4E, a restricting layer 34 for an
etching direction is disposed surrounded a side wall of the thermal
runaway suppression element 10. The restricting layer 34 is less
sensitive to external environmental variation than that of the
protecting layer 18 and the capsule 26. The two end surfaces of the
restricting layer 34 are adjacent to or disposed to the current
collectors 301, 302 of the batteries 30. The above-mentioned
external environmental variation is a change in temperature, pH or
electrolyte concentration. For example, in case of the external
environment variation is temperature, under such structure,
compared to the restricting layer 34, the capsule 26 or the
protecting layer 18 will be destroyed first caused by the
temperature variation. Therefore, the passivation composition
supplier 12 and the polar solution supplier 14 contained therein
will be released. Also, because the surrounding restricting layer
34 is not damaged, the released ions or the polar solution are
restricted inside surrounding area of the restricting layer 34. The
etching direction will be constrained to the current collector 301.
The above-mentioned restricting layer 34 may be mad of
silicone.
[0058] Please refer to FIG. 4F, in this embodiment, the open-side
surface of the positive current collector 301 has a plurality of
grooves 36 with openings. The thermal runaway suppression element
10 is filed in the groove 36. Therefore, the sidewall of the groove
36 can be used to limit the etching direction of the thermal
runaway suppression element 10. Or, as shown in FIG. 4G, a
plurality of bumps 38 are located on the positive current collector
301. The bumps 38 are made of a metal, a glass or a polymer, which
is inert to thermal runaway suppression element 10. The bumps 38
and the portions exposed from the bumps 38 of the positive current
collector 301 are form the grooves 36 for storing the thermal
runaway suppression element 10. Or the open side surface of the
positive current collector 301 includes a plurality of auxiliary
slots 37, which do not penetrate through thereof. The auxiliary
slots 37 is used to facilitate etching, as shown in FIG. 4H.
[0059] Continuing, it is to observe that the influences of the
thermal runaway suppression element of this invention acting to the
positive active materials with lithium-ion extraction and the
negative active materials with lithium-ion insertion. In this
experiment, the positive active material is NMC811, and the
negative active material is silicon-carbon.
[0060] Please refer to FIG. 5A, which is an XRD diffraction pattern
in which the concentrations of 30% NaOH, 30% NaAl(OH).sub.4, 30%
NaCl, 10% LiOH, and 30% KOH react with the positive active material
with lithium-ion extraction. It can be seen from the figure that
after the NMC811 with lithium-ion extraction reacts with sodium
ions, the characteristic peak (pointed by the arrows) of NMC811 is
no longer existed, and the lattice structure has been changed due
to the insertion of sodium or potassium ions. This may be because
comparing to lithium ions, the sodium/potassium ions with larger
sizes, heavier weight and higher potential energy obtain electrons
on the surface of the positive active material to form
sodium/potassium atoms. And by driving of the generated thermal
energy, they will migrate to the intercalations with the
lithium-ion extraction to form a structure with more stable and
lower electrochemical potential energy.
[0061] Please refer to FIG. 5B, which is the XRD diffraction
pattern before and after the negative active material with
lithium-ion insertion reacts with sodium/potassium ions and
aluminum ions. It can be clearly found that the characteristic
peaks representing Li--Si alloys have completely disappeared. It
means that the Li--Si alloys have become polymer compounds with
lower energy. It can be speculated that the sodium/potassium ions
and the aluminum ions will form an inorganic polymer, i.e.
geopolymer, with the silicon-carbon. The structure of this polymer
is M.sub.n[--(SiO.sub.2).sub.z--AlO.sub.2].sub.n.wH.sub.2O, where z
is the molar ratio of Si/Al atoms, Z=1, 2, 3 or greater than 3, M
is a cation, such as potassium ion (K.sup.+) or sodium ion
(Na.sup.+), n is the degree of polymerization, and w is the molar
amount of the crystal water. This inorganic compound is a closed
frame structure similar to zeolite, so it can transfer the negative
active materials with lithium-ion insertion into a state with
higher electric potential and lower energy.
[0062] Please refer to FIGS. 6A and 6B. FIG. 6A shows the voltage
and temperature curve for the thermal runaway testing of a
conventional lithium battery cell. FIG. 6B shows the voltage and
temperature curve for the lithium battery cell performing thermal
runaway suppression of the present invention. As shown in the
figures, when the thermal runaway is occurred and generating heat,
the voltage of the conventional lithium battery cell begins to drop
down after the temperature reaches around 500.degree. C. However,
for the lithium battery cell with thermal runaway suppression of
the present invention, the voltage begins to drop down after the
temperature reaches around 100.degree. C. by blocking the
electrochemical reaction pathway to effectively avoid the thermal
runaway.
[0063] FIGS. 7A to 7C are the images for the results of dropping
different solutions selected from pure water, NaOH.sub.(aq) and
NaAl(OH.sub.4).sub.(aq) respectively on a cathode with a 100%
SOC(state of charge). In FIG. 7A, it can be seen that the cathode
does not react with pure water. In FIGS. 7B and 7C, it can be seen
that NaOH.sub.(aq) and NaAl(OH.sub.4).sub.(aq) form the droplets in
hydrophobic state on the surface of the cathode, and a plurality of
tiny bubbles are presented in the droplets.
[0064] FIGS. 8A to 8C are the images for the results of dropping
different solutions selected from pure water, NaOH.sub.(aq) and
NaAl(OH.sub.4).sub.(aq) respectively on an anode with a 100%
SOC(state of charge). In FIG. 8A, it can be seen that the remaining
lithium in the anode reacts strongly to pure water and causes the
anode to crack. In FIGS. 8B and 8C, it can be seen that
NaOH.sub.(aq) and NaAl(OH.sub.4).sub.(aq) form the inorganic
polymer with bubbles, such like a foam, on the surface of the
anode. Also, a part of the inorganic polymer can be clamped by a
jig, as shown in FIG. 8D.
[0065] FIGS. 9A and 9B are SEM diagrams of the cathode with a 40%
SOC and with a 100% SOC respectively, which 30% sodium hydroxide
was dropped over about 1 hour, DMC(dimethyl carbonate) and a pure
water were used for surface cleaning, and then dried at 60.degree.
C. for 8 hours. As shown in the figures, for the cathode with a 40%
SOC, due to the lower lithium-ion extractions, the situation of
sodium ions are inserted to the positive of the lithium-ion
extractions of the cathode are not significant. However, the
undulations of the topography of the surface for the cathode become
significant. For the cathode with a 100% SOC, due to the higher
lithium-ion extractions, the situation of sodium ions are inserted
to the positive of the lithium-ion extractions of the cathode are
very significant. The relocation of the lattice and the undulations
of the topography of the surface for the cathode with a 100% SOC
are also very significant. And it can be observed that parts of the
surface even has a cracked state.
[0066] FIGS. 10A and 10B are SEM diagrams of the anode with a 40%
SOC and with a 100% SOC respectively, which 30% sodium hydroxide
was dropped over about 1 hour, DMC and a pure water were used for
surface cleaning, and then dried at 60.degree. C. for 8 hours. As
shown in the figures, the sodium hydroxide makes parts of the anode
with a 40% SOC form an inorganic polymer (geopolymer), and it also
has a needle-like structure of the colloidal silica acid. For the
anode with a 100% SOC, the needle-like structure is more
obvious.
[0067] Further, to verify the above-mentioned lower energy of the
cathode and the anode, please refer to FIGS. 11A and 11B, which are
thermograms of the differential scanning calorimeter for the
cathode and the anode using 20% NaAl(OH.sub.4).sub.(aq). It can be
clearly seen that a peak of the heat flow of the cathode at about
210.degree. C. has obviously disappeared, see FIG. 11A, and a peak
of the heat flow of the anode at about 180.degree. C. has obviously
disappeared, see FIG. 11B.
[0068] Thus, the thermal runaway suppression element can transfer
the positive active material with lithium-ion extraction from an
original state with higher electric potential and higher energy to
a crystalline state of the metal oxide with lower electric
potential and lower energy, and the negative active material with
lithium-ion insertion from an original state with lower electric
potential and higher energy to an inorganic polymer state with
higher electric potential and lower energy. Therefore, the voltage
of the whole battery is decreased and the electrochemical reaction
pathway is blocked.
[0069] Accordingly, the present invention provides a thermal
runaway suppression element of lithium batteries and the related
applications. When the temperature of the lithium battery reaches
to the predetermined temperature, such as 70-130.degree. C., the
aluminum current collector to etched through by the aluminum
etching ion to act as a path to enter the inside of the
electrochemical reaction system. Via the path, the metal ion (A)
and the aluminum ion, generated during the etching, are seeped into
the electrochemical reaction system and react with the positive
active material with lithium-ion extraction and the negative active
material with lithium-ion insertion to a state with lower energy.
The voltage of the whole battery is decreased and the
electrochemical reaction pathway is blocked to prevent the thermal
runaway from occurring. Moreover, comparing to the conventional
arts, the method for suppressing thermal runaway of the invention
is performed directly on the active materials that generate the
maximum energy to cause the thermal runaway and being the main
reaction body of the entire electrochemical reaction. Also, the
metal ion (A) will be driven by acquired thermal energy to fill the
positive of the lithium-ion extraction or intercalation, and
relocate the lattice to form a new stable state, and at the same
time, the thermal energy is consumed. Also, the release of oxygen
caused by structural instability and the chain uncontrollable
reaction derived therefrom are suppressed. The negative active
materials with lithium-ion insertion will act with the metal ion
(A), such as a non-lithium alkali metal ion, an alkaline earth
metal ion or a combination thereof, and the aluminum ion to form a
polymer compounds with lower energy. Therefore, both of the
positive active materials and the negative active materials would
stay with lower energy to improve safety of the lithium batteries,
and terminate the thermal runaway of the lithium battery
effectively and quickly. Furthermore, due to the thermal runaway
suppression element is disposed outside the lithium battery, it
will not affect the efficiency or composition of the
electrochemical reaction system of the lithium battery.
[0070] The invention being thus described, it will be obvious that
the same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be obvious to one skilled in
the art are intended to be included within the scope of the
following claims
* * * * *